A tiny sea snail known as the clusterwink snail has one of the strangest abilities in the animal kingdom. The snail can create a ghostly green light, then use its shell to scatter the light beam all over its shell.

The snail seems to use its bioluminescence as a defense mechanism, as recent experiments revealed that the snail turned green whenever a threatening crab or shrimp came near the snail. Researchers at UC San Diego suspect the bioluminescence is used to create the illusion of a larger animal whenever potential predators approach. Nerida Wilson explains why this find is so unusual:

"It's rare for any bottom-dwelling snails to produce bioluminescence. So it's even more amazing that this snail has a shell that maximizes the signal so efficiently."

Indeed, the snail's shell appears to be completely opaque, which one would think would block any escaping light. But the shell actually works to very specifically control how light diffuses from the shell. When the snail creates bioluminescent light, its shell makes sure only that particular green color is dispersed.

It's an unusual adaptation, and one that the researchers hope can be used in optics and bioengineering. Dmitri Deheyn explains:

"The light diffusion capacity we see with this snail is much greater than comparative reference material. Our next focus is to understand what makes the shell have this capacity and that could be important for building materials with better optical performance."